There are various schools of thought on the use of declarations in patent prosecution. To be sure, there are significant pitfalls when using declarations that can significantly impact claim scope and validity. Nevertheless, in some instances additional evidence may be the only practical way to obtain an allowance without significant cost and delay.
For those managing a large portfolio for a particular applicant, usually there are cases of technology overlap due to the nature of technology development. Examiners often prefer to cite an applicant's own previous application in a rejection of a follow-on improvement. One reason is that it can make many aspects of the rejection relatively easy due to similar wording, figures, etc.
Sometimes, however, the USPTO's penchant for citing the applicant's own references can be used to advantage, particularly where an Examiner improperly interprets disclosure in the prior application. For example, where the prior art reference being used has an inventor that is still available (e.g., because that inventor still works for the applicant), that inventor may be able to provide evidence, through a declaration, of what her application actually shows. Such evidence can carry substantial weight - after all, she was the inventor so she should know what was disclosed and how it would be understood by a person of ordinary skill in the art. The declaration can also comment on the non-obviousness of the new approach, and why the cited reference potentially points away from the new improvement. In some ways, there can be no better evidence of whether a prior art reference shows or suggests certain features than a statement by the inventors of that application. Such evidence can be particularly valuable on appeal, where PTAB judges seem to greatly enjoy knocking down technical arguments of counsel by noting that they are mere attorney argument unsupported by any evidence of record.
So, next time the applicant's own reference is cited and misinterpreted by the Examiner, consider whether it is possible for the inventors of that reference to refute the technical assertions of the Office via a declaration.